// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/loader/resource_buffer.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace content {

TEST(ResourceBufferTest, BasicAllocations)
{
    scoped_refptr<ResourceBuffer> buf = new ResourceBuffer();
    EXPECT_TRUE(buf->Initialize(100, 5, 10));
    EXPECT_TRUE(buf->CanAllocate());

    // First allocation
    {
        int size;
        char* ptr = buf->Allocate(&size);
        EXPECT_TRUE(ptr);
        EXPECT_EQ(10, size);
        EXPECT_TRUE(buf->CanAllocate());

        EXPECT_EQ(0, buf->GetLastAllocationOffset());

        buf->ShrinkLastAllocation(2); // Less than our min allocation size.
        EXPECT_EQ(0, buf->GetLastAllocationOffset());
        EXPECT_TRUE(buf->CanAllocate());
    }

    // Second allocation
    {
        int size;
        char* ptr = buf->Allocate(&size);
        EXPECT_TRUE(ptr);
        EXPECT_EQ(10, size);
        EXPECT_TRUE(buf->CanAllocate());

        EXPECT_EQ(5, buf->GetLastAllocationOffset());

        buf->ShrinkLastAllocation(4);
        EXPECT_EQ(5, buf->GetLastAllocationOffset());

        EXPECT_TRUE(buf->CanAllocate());
    }
}

TEST(ResourceBufferTest, AllocateAndRecycle)
{
    scoped_refptr<ResourceBuffer> buf = new ResourceBuffer();
    EXPECT_TRUE(buf->Initialize(100, 5, 10));

    int size;

    buf->Allocate(&size);
    EXPECT_EQ(0, buf->GetLastAllocationOffset());

    buf->RecycleLeastRecentlyAllocated();

    // Offset should again be 0.
    buf->Allocate(&size);
    EXPECT_EQ(0, buf->GetLastAllocationOffset());
}

TEST(ResourceBufferTest, WrapAround)
{
    scoped_refptr<ResourceBuffer> buf = new ResourceBuffer();
    EXPECT_TRUE(buf->Initialize(20, 10, 10));

    int size;

    buf->Allocate(&size);
    EXPECT_EQ(10, size);

    buf->Allocate(&size);
    EXPECT_EQ(10, size);

    // Create hole at the beginnning.  Next allocation should go there.
    buf->RecycleLeastRecentlyAllocated();

    buf->Allocate(&size);
    EXPECT_EQ(10, size);

    EXPECT_EQ(0, buf->GetLastAllocationOffset());
}

TEST(ResourceBufferTest, WrapAround2)
{
    scoped_refptr<ResourceBuffer> buf = new ResourceBuffer();
    EXPECT_TRUE(buf->Initialize(30, 10, 10));

    int size;

    buf->Allocate(&size);
    EXPECT_EQ(10, size);

    buf->Allocate(&size);
    EXPECT_EQ(10, size);

    buf->Allocate(&size);
    EXPECT_EQ(10, size);

    EXPECT_FALSE(buf->CanAllocate());

    // Create holes at first and second slots.
    buf->RecycleLeastRecentlyAllocated();
    buf->RecycleLeastRecentlyAllocated();

    EXPECT_TRUE(buf->CanAllocate());

    buf->Allocate(&size);
    EXPECT_EQ(10, size);
    EXPECT_EQ(0, buf->GetLastAllocationOffset());

    buf->Allocate(&size);
    EXPECT_EQ(10, size);
    EXPECT_EQ(10, buf->GetLastAllocationOffset());

    EXPECT_FALSE(buf->CanAllocate());
}

TEST(ResourceBufferTest, Full)
{
    scoped_refptr<ResourceBuffer> buf = new ResourceBuffer();
    EXPECT_TRUE(buf->Initialize(20, 10, 10));

    int size;
    buf->Allocate(&size);
    EXPECT_EQ(10, size);

    buf->Allocate(&size);
    EXPECT_EQ(10, size);

    // Full.
    EXPECT_FALSE(buf->CanAllocate());

    // Still full, even if there is a small hole at the end.
    buf->ShrinkLastAllocation(5);
    EXPECT_FALSE(buf->CanAllocate());
}

} // namespace content
